The invention concerns a hydraulic vane machine with a stator having a stator bore with a guiding contour, a rotor arranged in the stator bore and having substantially radially movable vanes bearing on the guiding contour, and a shaft connected fixedly rotatable with the rotor via a coupling.
Such machines are known both as motors (U.S. Pat. No. 4,376,620; U.S. Pat. No. 3,254,570) and as pumps (U.S. Pat. No. 3,255,704). For convenience the following description is based on a motor.
In one section, the diameter of the guiding contour of the stator bore is approximately equal to the diameter of the rotor. In another section the diameter of the guiding contour is larger. Between these two sections there are transition sections. When the rotor rotates, the vanes will extend radially outwards in the larger sections, and can then be exposed to the pressure of a hydraulic fluid. This pressure causes the production of a torque, which turns the rotor. At the end of the section with the increased diameter the vanes are retracted into the rotor, and the pressurised fluid is drained off, e.g. to a tank connection.
In this connection the vanes, together with the rotor, the stator and side walls, enclose cells, also named vane cells. It is obvious that during operation some limiting walls of the vane cells are movable in relation to the cells. When the side plates are stationary in the stator, the side walls are movable relative to the cells. The sealing towards the rotor is required. When the side walls rotate with the rotor, they stand still in relation to the cells. However, then the side walls must turn in relation to the stator, meaning that the sealing will be required here.
Such a sealing is practically only available, when the corresponding parts bear on each other with a certain pressure. However, this causes increased frictional values and a corresponding wear. This again leads to undesired leakages.
Attempts can be made to realise a dimensioning, which will keep the forces acting on the individual parts in balance. However, this is usually only possible for specific operation conditions. E.g. when the shaft is loaded unilaterally, unequal forces occur on the contact surfaces between stator and rotor, which are practically impossible to balance. Such a constellation e.g. occurs when the shaft is loaded unilaterally in the radial direction. This is the case when driving e.g. a vee belt or a toothed belt. Here the shaft is pulled in a certain direction by the tension of the belt, which normally leads to a small tilting of the rotor, which will have the detrimental effects described above.
It is the task of the invention to improve the operational behaviour of a hydraulic vane machine.